A plunge router is typically designed with a separate motor housing and base that are assembled together to form the overall unit. The base typically rests on a router table or the workpiece surface, and has vertical supports or shafts upon which the motor housing may be mounted. The motor housing is mounted on these supports in a way that allows it to slide up or down relative to the base. This configuration allows the motor to be activated prior to lowering the motor housing toward the base and causing the rotating cutting blade of the router to engage the workpiece. When the proper depth-of-cut is attained, the motor housing can then be locked in this position relative to the base until the cut is finished.
Plunge routers, therefore, need some type of mechanism that prevents further travel of the motor housing relative to the base once the cutting blade reaches the desired depth-of-cut. These mechanisms, often referred to as depth stops, are known in the art and are either inexpensive, such as a simple thumb screw depth stop, or are very complex, such as the more expensive multi-position turret depth stop. One difficulty, in particular, when using a simple thumb screw depth stop is obtaining the desired accuracy needed for the particular depth-of-cut. Some prior art designs use printed scales to measure cutting blade positions, however, when dealing with very fine increments, the operator may have difficulty visually discerning one location on the scale from the next.